Steam-trap



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i NELSONOURTIS, OF NEWTON, MASSACHUSETTS.

STEAM-TRAP.

SPECIFICATION forming` Ypart of lLetters Patent No. 253,985, dated February 21, 1882. Application filed December 14, 188l. (No model.)

To all whom tt may concern: l

Be it known that I, NELSON CURTIS, of Newton, in the State of Massachusetts, ham in-V valve being connected with the walls of the wa v ter-chamber in such manner that the valve is operated bythe difference in the rates of expansion ofthe metal ofthe valve-stem and the metal of the walls of the watechamber.

In the drawings, Figure 1 is a sectional elevation of apparatus embodying my said invention; and Fig. 2 is an elevation of a casting embodying my said invention in part, as will hereinafter appear.

Ais the water-chamber,consisting in this in stance of a long pipe adapted to receive steam and water from other pipes, and having a capacity for expansion longitudinally.

B is a casting, within which is a chamber, a, .closed above and below by caps B and B2. It has two hollow projections,B3 and B4,the former screwing upon the water pipe or chamber A and thelatter adapted to receive an outlet-pipe. For the purpose of this description, however, these two passages, with the chamber a, may be considered as themselves forming the main passage through which water is to be allowed to escape, a wall, w, in the said chamber cona taining the main port p and affording aseat for the piston-valve C, whose stem extends through the port p and into the capB2, as shown. The acting areas of the valve-port and of the piston are proportioned substantially as shown. The piston ts loosely in the chamber a to permit the passage of water and steam from its lower to its upper side; Itis hollowed out above, as shown v The casting B has at one side a flange, B5,

within which is a narrow passage, f, connecting that part of the chamber a which lies above therpiston with thatV part which lies below the port p.

D is a thermostatic valve having bearings in ahole bored in a boss, BG, which projects from the flange B5 within the projection B3, and sliding across thelower end ofthe passagefto open or close a port, pf, at the lower entrance of the passage j' into the chamber a.. The areas of the passage f and port p are greater than that of the aperture formed by the loose fit of the piston in chamber a.

The stem of the thcrmostatic valve p' in the apparatus shown is of one piece with the said valve, but might be made of a separate piece of metal. Its free end is screwed into a perforated adjustingnut, N, which is at the farther end of the water-chamber A and forms a packing for a union-joint, by which the said water-chamber is connected with the steam system to which it belongs. The stem of the valve D is made of metal which expands and contracts to a much greater degree than the walls of the water-chamber A under the same increase and decrease of temperature.

A spring, S, in the apparatus shown tends to keep the piston-valve closed; but the pistonvalve may be of sufficient weight to do away with the need of a spring.

When the apparatus is notin use the pistona valve C is normally closed, but it is normally open when there is sufficient steam in the pipes with which the apparatus is connected to make it desirable to use the trap. The valve D is also normally open, and so remains until there is sufficient heat in the water-chamber to close it bythe expansion of the valve-stem. While the valve D is open, thereby reducing the pressure upon the top of the piston, the piston-valve C also remains open, and the condensed water inthe water-chamber A-ows freely through the port p,- but when the temperature in the water-chamber A is high enough to close the valve D the` pressure above the piston accumu; lates, and, there being an unbalanced area in the top of the piston, closes the piston-valve, and thereupon no water or steam escapes from the water-chamber A.

In the description thus far it has been assumed that the water-chamber A, containing iceV 1o from the casting B into the Water-chamber.

I claim- Amain passage forsteam or other Huid under pressure and a piston-valve therein, a smaller passage connecting the two portions of the main passage which lie on either side of the port of I5 thepistolrvalve, and athermostatio valve withiu said smaller passage, in combination with the steam-tightwater-chamber of a steam-trap, the stem ofthe thermostatic valve extending into and connected with said Water-chamber, substantial] y asdesoribed,forthe purpose specified.

NELSON CURTIS.

Vitnesses W. W. SWAN, W. P. PREBLE, J r. 

